Some questions about SD cards


Agricola

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Hello ED,

You've often stated that a user can choose between the internal eMMC and a microSD card as a boot medium. How is that going to happen? Will the Pyra register an inserted SD card and just boot of it or is there going to be a DIP switch or something similar to let the user pick the eMMC even with an inserted microSD?

Also, what is the maximum supported speed of the SD cards? Do they use the same controller and are thereby limited to its speed when accessing both at the same time?
 

EvilDragon

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It's possible to hardware-force-boot from the MicroSD card via key combination when switching on.

In the end, the bootloader should fully handle this and it should be user configurable from where it boots as default and how to change it.

The switch to choose between emmc and sd card is software controllable, so a bootloader can do that.
 

Askarus

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Also, what is the maximum supported speed of the SD cards? Do they use the same controller and are thereby limited to its speed when accessing both at the same time?

AFAIK the big SD-cards are independent.

Only emmc and microSD have to share the lines.

Don't know the speed.
 
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WizardStan

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The eMMC channel is capable of SDR104.  That means about 100MB/s for compatible SDXC cards and 200MB/s for eMMC.  The actual speed would depend on the capabilities of the cards themselves, and that's the max theoretical so we can't really say what it will be practically.

The large SD cards are SDR50, double the theoretical max of the Pandora, so expect at least 32MB/s for high speed cards, upwards of 50MB/s.
 

matzesu

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Got me a 128 gb SDHC Card some months ago, they even work at Pandora :)

By the way: there will be a new Filesystem at Pyra , no PND,

But can i still put my Roms at the SD Card in a Rom Folder on Root??

I think the Programms will need a diverent folder, but the Romdirektory should be the same..
 

levi

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Yes, you can mostly put ROMs in a rom folder in the root.  A couple of emulators require you to put them inside their appdata instead as I recall, but none that I regularly use.  The format of those files is unlikely to change, having not originated with the Pandora or the emulator that runs them.

FWIW, the actual filesystem is unlikely to change.  The Pyra should still support the ext-formats and FAT32, but the PND file format won't be supported for 'native' apps, and probably not at all at launch at least.  It won't break the Pyra if you insert an SD card full of PND files though, and as you say you'll probably need a 'pyra' folder or something to put the Pyra DBPs (or what have you) in.
 

matzesu

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Ok, so i think i wants to start to copy the roms over at weekend, thanks to the Pandora whit it 2 SD Slots.., this should be realy fast..
 
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